Showing papers on "Iodine published in 2006"

Effect of iodine intake on thyroid diseases in China.

Abstract: Background Iodine is an essential component of thyroid hormones; either low or high intake may lead to thyroid disease. We observed an increase in the prevalence of overt hypothyroidism, subclinical hypothyroidism, and autoimmune thyroiditis with increasing iodine intake in China in cohorts from three regions with different levels of iodine intake: mildly deficient (median urinary iodine excretion, 84 μg per liter), more than adequate (median, 243 μg per liter), and excessive (median, 651 μg per liter). Participants enrolled in a baseline study in 1999, and during the five-year follow-up through 2004, we examined the effect of regional differences in iodine intake on the incidence of thyroid disease. Methods Of the 3761 unselected subjects who were enrolled at baseline, 3018 (80.2 percent) participated in this follow-up study. Levels of thyroid hormones and thyroid autoantibodies in serum, and iodine in urine, were measured and B-mode ultrasonography of the thyroid was performed at baseline and follow-up. Results Among subjects with mildly deficient iodine intake, those with more than adequate intake, and those with excessive intake, the cumulative incidence of overt hypothyroidism was 0.2 percent, 0.5 percent, and 0.3 percent, respectively; that of subclinical hypothyroidism, 0.2 percent, 2.6 percent, and 2.9 percent, respectively; and that of autoimmune thyroiditis, 0.2 percent, 1.0 percent, and 1.3 percent, respectively. Among subjects with euthyroidism and antithyroid antibodies at baseline, the five-year incidence of elevated serum thyrotropin levels was greater among those with more than adequate or excessive iodine intake than among those with mildly deficient iodine intake. A baseline serum thyrotropin level of 1.0 to 1.9 mIU per liter was associated with the lowest subsequent incidence of abnormal thyroid function. Conclusions More than adequate or excessive iodine intake may lead to hypothyroidism and autoimmune thyroiditis.

Effect of Bromide and Iodide Ions on the Formation and Speciation of Disinfection Byproducts during Chlorination

Abstract: Two natural waters were fortified with various levels of bromide or iodide ions (0−30 μM) and chlorinated in the laboratory to study the impact of bromide and iodide ions on the formation and speciation of disinfection byproducts. Trihalomethanes (THMs), haloacetic acids (HAAs), total organic halogen (TOX), and its halogen-specific fractions total organic chlorine (TOCl), bromine (TOBr), and iodine (TOI), were measured in this work. The molar yields of THMs and HAAs increased as the initial bromide concentration increased. No significant change in TOX concentration was found for varying bromide concentrations. However, TOX concentrations decreased substantially with increasing initial iodide concentrations. At higher levels of bromide, there was a decreasing level of unknown TOX and unknown TOCl but an increasing level of unknown TOBr. The extent of iodine substitution was much lower than that of bromine substitution when comparing identical initial concentrations because a substantial amount of iodide wa...

The Danish investigation on iodine intake and thyroid disease, DanThyr: status and perspectives

Abstract: Objective: Denmark was an area of iodine deficiency, and mandatory iodine fortification of table salt and salt in bread (13 p.p.m. iodine) was initiated in 2000/2001. The Danish investigation on iodine intake and thyroid disease (DanThyr) is the monitoring of the iodine fortification program. Design and methods: DanThyr consists of three main parts: a study of population cohorts initialized before (nZ4649) and after (nZ3570) iodization of salt, a prospective identification of incident cases of overt hyper- and hypothyroidism in a population of around 550 000 people since 1997, and compilation of data from the national registers on the use of thyroid medication, thyroid surgery, and radioiodine therapy. Studies were carried-out in parallel in subcohorts living in areas with differences in iodine content of ground water. Results: The study showed profound effects of even small differences in iodine intake level on the prevalence of goiter, nodules, and thyroid dysfunction. Mild and moderate iodine deficiency was associated with a decrease in serum TSH with age. Other environmental factors were also important for goiter development (increase in risk, smoking and pregnancy; decrease in risk, oral contraception and alcohol consumption), and the individual risk depended on the genetic background. Environmental factors had only a minor influence on the prevalence of thyroid autoantibodies in the population. There were more cases of overt hypothyroidism in mild than in moderate iodine deficiency caused by a 53% higher incidence of spontaneous (presumably autoimmune) hypothyroidism. On the other hand, there were 49% more cases of overt hyperthyroidism in the area with moderate iodine deficiency. The cautious iodine fortification program, aiming at an average increase in iodine intake of 50 mg/day has been associated with a 50% increase in incidence of hyperthyroidism in the area with the most severe iodine deficiency. The incidence is expected to decrease in the future, but there may be more cases of Graves’ hyperthyroidism in young people. Conclusion: A number of environmental factors influence the epidemiology of thyroid disorders, and even relatively small abnormalities and differences in the level of iodine intake of a population have profound effects on the occurrence of thyroid abnormalities. Monitoring and adjustment of iodine intake in the population is an important part of preventive medicine.

Perchlorate versus other environmental sodium/iodide symporter inhibitors: potential thyroid-related health effects

Abstract: Objective: Perchlorate is a known competitive inhibitor of the sodium/iodide symporter (NIS). Possible thyroid-related effects of environmental perchlorate have created great health concerns, especially in the US, resulting in a debated reference dose (RfD) of 0.0007 mg/kg per day in drinking water recommended by the National Academy of Sciences (NAS). However, the impact of other environmental NIS inhibitors and the role of iodine seem to have received little attention in the whole debate. Methods: We performed a PubMed search for articles published up to February 2006, using the key terms perchlorate, nitrate, thiocyanate, iodine, NIS, RfD, thyroid (alone or in combinations), with particular attention for human studies. In parallel, we critically analysed the January 2005 NAS’ report, entitled ‘Health implications of perchlorate ingestion’. Results: The relative potencies of prevalent environmental NIS inhibitors (nitrate, thiocyanate and perchlorate) to inhibit iodine uptake have been estimated repeatedly with robust results. Our calculations show that nitrate and thiocyanate, acquired through drinking water or food, account for a much larger proportion of iodine uptake inhibition than perchlorate. Furthermore, the iodine uptake inhibitory effects of nitrate and thiocyanate – as defined by their legally accepted maximal contaminant levels in drinking water – exceed the potential effect of the proposed RfD for perchlorate by far. Conclusions: Iodine uptake inhibition and any potential downstream effect by perchlorate are highly dependent on the presence of other environmental NIS inhibitors and iodine intake itself. These potential confounders should therefore be considered in future studies and calculations for risk assessment.

Temporal patterns in perchlorate, thiocyanate, and iodide excretion in human milk

Abstract: Breast milk is widely recognized as the best source of nourishment for infants (Gartner et al. 2005). Breast-feeding also fosters an infant’s emotional and social well-being (Else-Quest et al. 2003; Winberg 2005). The American Academy of Pediatrics (Gartner et al. 2005), World Health Organization (WHO 2001), and the International Council of Nurses (ICN 2006) all recommend that infants be exclusively breast-fed for the first 6 months of life. It is important that milk be as free of detrimental agents as possible (LaKind et al. 2004); it is also important that the maternal diet provides the nutrients needed for high milk quality (Dorea 2002). This is especially true for iodine. Iodine deficiency is widely recognized as the leading and most readily preventable cause of mental impairment in children (Delange et al. 2001). Unlike adults, neonates do not have significant thyroxine stores (van den Hove et al. 1999). Exclusively breast-fed infants depend on their mother’s milk iodine for thyroid hormone (TH) synthesis and establishment of TH stores from which they can draw TH if iodine availability falls. Thyroid hormones and therefore iodine are essential to fetal and infant neurodevelopment. Infants born to hypothyroid- or iodine-deficient women exhibit intellectual and behavioral deficits as children (Rovet and Ehrlich 2000). Such deficits may be apparent in infants as young as 3 weeks even if the degree of early deficiency was small or transient or occurred during fetal development (Kooistra et al. 2006). The Institute of Medicine (IOM 2001) recommends an iodine intake of 110 μg/day for infants 0–6 months of age, and 130 μg/day for infants 7–12 months of age. Iodine needs of pre-term infants may be twice what is needed by full-term infants (Ares et al. 2005). Breast milk–iodine content is considered sufficient when levels are 150–180 μg/L (Delange 2004). Milk samples provided by most women in our previous study (Kirk et al. 2005) fell far short of this standard. The median iodide level in human milk from 23 donors residing in 15 different states (Kirk et al. 2005) was 33.5 μg/L, and only 4 samples fell within the recommended level. We have therefore been concerned that lactating women in the United States may not be consuming sufficient iodine to meet the needs of their breast-fed infants. Exposure to perchlorate and other iodide transport inhibitors may increase the risk of iodine deficiency among infants. The sodium–iodide symporter (NIS) is 30-fold more selective for perchlorate than for iodide and is reportedly 9–100 times as potent as thiocyanate in inhibiting iodide uptake (Dohan et al. 2003; Tonacchera et al. 2004). Perchlorate and other iodide transport inhibitors such as thiocyanate thus likely reduce transfer of iodide to breast milk at the mammary NIS. Unless major dietary changes have occurred after the birth of her child, it is also likely that a woman with perchlorate and/or thiocyanate in her milk was similarly exposed during pregnancy, potentially reducing the pool of maternal TH needed for fetal development and reducing the ability of the fetal thyroid to produce its own hormones. For a nursing infant, the production of TH would be dually impaired: first by reduction of breast-milk iodide content and then by reduced iodide uptake by the infant thyroid. A discrimination factor of 30× at both stages amounts to 3 orders of magnitude of discrimination overall. Various aspects of brain development depend precisely on when TH deficiency occurs. An infant who had insufficient TH during fetal life might suffer delay or impairment in neurologic functions that develop in utero. This infant may suffer other impairments if TH deficiency occurs again, or continues, after parturition. Transient or mild hypothyroidism during fetal or infant development may result in long-standing, possibly permanent functional deficits that include learning disabilities and hyperactivity (Haddow et al. 1999; Morreale de Escobar et al. 2000; Rovet 2002, 2005; Pop et al. 1999). Some find strong links between iodine deficiency and attention deficit disorders (ADD; Vermiglio et al. 2004). In the United States, an estimated 3–5% of children (approximately 2 million) have ADD (National Institute of Mental Health 2003). A lack of data on the variability of iodide excretion limits our ability to assess milk iodine levels. Most studies of human milk iodide, including our own, have been based on single samples (Ciardelli et al. 2002; Skeaff et al. 2005), although a few have examined iodide content in samples from two (Gushurst et al. 1984; Moon and Kim 1999) or three points in time (Chierici et al. 1999). These measures may not accurately portray infant intake, especially if samples were systematically collected at times when iodide content is low. The same holds for perchlorate in milk. Although perchlorate may be common in human milk, nothing is known about the temporal variation of perchlorate levels. Finally, thiocyanate, a by-product of cyanide metabolism, is also found in human milk. We describe the variation of iodide, perchlorate, and thiocyanate levels in series of human milk samples. The implications for infant development are discussed.

Iodine nutrition--more is better.

Abstract: In normal adults, the daily production rate of the two biologically active thyroid hormones, tetraiodothyronine (which is better known as thyroxine and has four iodine atoms) and triiodothyronine (which has three), is approximately 100 μg and 30 μg, respectively. All of the thyroxine, but only about 20 percent of the triiodothyronine, is produced by the thyroid gland; the remainder of the triiodothyronine is produced through the extrathyroidal deiodination of thyroxine. A minimum of approximately 70 μg of iodine is therefore needed to produce these two hormones in the thyroid gland each day. But more than that is required, because iodine . . .

The loss of the chloride channel, ClC-5, delays apical iodide efflux and induces a euthyroid goiter in the mouse thyroid gland.

Abstract: Genetic inactivation of ClC-5, a voltage-gated chloride channel prominently expressed in the kidney, leads to proteinuria because of defective apical endocytosis in proximal tubular cells. Because thyroid hormone secretion depends on apical endocytosis of thyroglobulin (Tg), we investigated whether ClC-5 is expressed in the thyroid and affects its function, using Clcn5-deficient knockout (KO) mice. We found that ClC-5 is highly expressed in wild-type mouse thyroid ( approximately 40% of mRNA kidney level). The protein was immunolocalized at the apical pole of thyrocytes. In Percoll gradients, ClC-5 overlapped with plasma membrane and early endosome markers, but best codistributed with the late endosomal marker, Rab7. ClC-5 KO mice were euthyroid (normal T4 and TSH serum levels) but developed a goiter with parallel iodine and Tg accumulation (i.e. normal Tg iodination level). When comparing ClC-5 KO with wild-type mice, thyroid 125I uptake after 1 h was doubled, incorporation into Tg was decreased by approximately 2-fold, so that trichloroacetic acid-soluble 125I increased approximately 4-fold. Enhanced 125I- efflux upon perchlorate and presence of 125I-Tg as autoradiographic rings at follicle periphery demonstrated delayed iodide organification. Endocytic trafficking of 125I-Tg toward lysosomes was not inhibited. Expression of pendrin, an I-/Cl- exchanger involved in apical iodide efflux, was selectively decreased by 60% in KO mice at mRNA and protein levels. Thus, ClC-5 is well expressed in the thyroid but is not critical for apical endocytosis, contrary to the kidney. Instead, the goiter associated with ClC-5 KO results from impaired rate of apical iodide efflux by down-regulation of pendrin expression.

Differential regulation of apical and basal iodide transporters in the thyroid by thyroglobulin

Abstract: We have shown that thyroglobulin (Tg) is a potent autocrine regulator of thyroid-specific gene expression, and proposed that the accumulated follicular Tg within the colloid is a major factor in determining follicular function. In the present report, we examined the effect of Tg on the action of TSH/cAMP and iodine with special focus on the regulation of basolateral and apical iodide transporters; the sodium/iodide symporter (NIS) and the pendred syndrome gene (PDS) by Tg. We show that expression of NIS and PDS are differentially regulated by Tg concentration and exposure time. In addition, we found that PDS gene was induced by TSH/cAMP and iodide in the presence of Tg. Based on these results, we propose a model for the physiological turnover of follicular function that is dynamically regulated by Tg.

Lithium as adjuvant to radioiodine therapy in differentiated thyroid carcinoma: clinical and in vitro studies

Abstract: Summary Objective Lithium has been reported to increase radioactive iodine (RaI) doses in benign thyroid disease and in differentiated thyroid carcinoma (DTC). It is not known whether lithium influences the outcome of RaI therapy in DTC. We therefore studied the clinical effects of RaI without and with lithium carbonate in patients with proven metastatic DTC. Controversy also exists on the mechanism by which lithium increases RaI dose in DTC. We performed an in vitro study specifically aimed at examining the effects of lithium on the sodium iodide symporter (NIS). Design In a clinical study, 12 patients were selected with metastases of DTC who had received previous RaI therapy without lithium (control) that had not influenced tumour progression, despite RaI accumulation in metastases. The patients received 1200 mg lithium carbonate/day followed by 6000 MBq RaI. Outcome parameters were RaI uptake, serum thyroglobulin (Tg) levels and radiological dimensions of metastases compared between RaI with lithium and control. In an in vitro study, iodide uptake was studied in the benign rat thyroid cell line FRTL-5, in the polarized non-thyroid MDCK cell line, stably transfected with human sodium iodide symporter (hNIS) to study the effects of lithium on NIS in a non-thyroid background, and the human follicular thyroid carcinoma cell line FTC133-hNIS to study lithium effects in a background of DTC. Lithium chloride (LiCl) was added in concentrations up to 2 mm for 0–48 h. Both steady-state iodide uptake (30 min) and initial rate (2 min) were studied using a specific activity of 100 mCi/mmol I, the latter experiment to determine lithium effects on substrate dependency. Iodide efflux studies were performed as well. Results Despite an increased uptake of RaI in seven patients, no beneficial effect of RaI with lithium was observed on the clinical course as assessed by serum Tg measurements and radiographically. In the in vitro studies, no effects of LiCl on iodide uptake or efflux were observed. Conclusions The addition of lithium to RaI did not have any beneficial effects on the clinical course in 12 patients with metastatic DTC. No beneficial effects of lithium on iodide uptake were observed in vitro. Therefore, the clinical value of lithium in DTC remains subject to debate.

Extending the clinical heterogeneity of iodide transport defect (ITD): a novel mutation R124H of the sodium/iodide symporter gene and review of genotype-phenotype correlations in ITD.

Abstract: Context: Iodide transport defect (ITD) is an autosomal recessive disorder resulting in varying degrees of congenital hypothyroidism (CH) with goiter and low or absent radioiodide uptake (RIUT), as determined by thyroid scintigraphy, and low iodide saliva to plasma ratio Defects of the sodium/iodide symporter gene (NIS) have been shown to cause ITD Objective: We describe molecular studies of NIS in a patient with ITD and genotype-phenotype correlation analysis in 31 patients with NIS defects reported worldwide Design: NIS sequencing and functional studies of the new NIS mutation in vitro were performed Results: In a newborn with symptomatic CH and a large goiter, thyroid scintigraphy showed no RIUT (0%) NIS sequencing identified the new homozygous mutation, R124H, in exon 2 This mutation was associated with abolition of iodide uptake in vitro when transfected in COS-7 cells Immunocytochemical studies documented correct targeting of the mutated protein to the plasma membrane of transfected cells Gen

Declining iodine content of milk and re-emergence of iodine deficiency in Australia.

Abstract: University hospitals in the United States are awash with seas of white coats. Doctors are readily identifiable, their name and clinical service clearly embroidered on their breast pockets. Students are also part of this white brigade, albeit in shorter coats. When asked why they persist with the white coat, long abandoned by their colleagues elsewhere in the world, their justification includes instant recognition by patient and public alike, ease of maintenance, and the white coat’s value as an integral part of the tradition and practice of medicine.

Availability of iodide and iodate to spinach (Spinacia oleracea L.) in relation to total iodine in soil solution

Abstract: A greenhouse pot experiment was carried out to investigate the availability of iodide and iodate to soil-grown spinach (Spinacia oleracea L.) in relation to total iodine concentration in soil solution. Four iodine concentrations (0, 0.5, 1, 2 mg kg−1) for iodide (I−) and iodate (IO 3 − ) were used. Results showed that the biomass productions of spinach were not significantly affected by the addition of iodate and iodide to the soil, and that iodine concentrations in spinach plants on the basis of fresh weights increased with increasing addition of iodine. Iodine concentrations in tissues were much greater for plants grown with iodate than with iodide. In contrast to the iodide treatments, in iodate treatment leaves accounted for a larger fraction of the total plant iodine. The soil-to-leaf transfer factors (TFleaf) for plants grown with iodate were about tenfold higher than those grown with iodide. Iodine concentrations in soil solution increased with increasing iodine additions to the soil irrespective of iodine species. However, total iodine in soil solution was generally higher for iodate treatments than iodide both in pots with and without spinach. According to these results, iodate can be considered as potential iodine fertilizer to increase iodine content in vegetables.

Deiodination of the iodinated amino acids.

Abstract: When iodotyrosines or iodothyronines labeled with are administered intravenously to normal man, most of the labeled iodine appears in the course of time in the urine as free inorganic iodide. Only negligible amounts of the undegraded parent substances pass the renal barrier intact. Evidently, there are mechanisms in the body that can remove iodine from the aromatic rings of these physiologically important substances and in the process reduce i t to its ionic form. Much effort has attended the study of these processes of deiodinization, for it has become apparent that they may be critical in ordering the metabolic impact of these compounds. Indeed, deficiencies of deiodination may underlie profound disturbances of growth and development.’ p 2 The problem of deiodination has been approached in many laboratories from many different points of view. Seemingly discordant results may be attributed to differences in technique and, perhaps more significantly, to differences in the events being measured. This review will survey the pathways and mechanisms of deiodination of the aromatic amino acids and their chemical relatives, as indicated by information obtained from both in vivo and in vitro studies.

Iodide excess exerts oxidative stress in some target tissues of the thyroid hormones

Abstract: Environmental iodine deficiency continues to be a significant public health problem worldwide. On the other hand, iodide excess results principally from the use of iodine-containing medicinal preparations or radiographic contrast media. For this reason we intended to explore iodide excess impairment on prooxidant/antioxidant balance of the thyroid gland, hepatic tissue and in blood and the effect of selenium administration on oxidative stress markers under the same circumstances. Experiments were performed for 10 days with white, male, Wistar rats, as follows: group 1: control-normal iodine supply group; 2: high iodine diet, group; 3: high iodine diet and selenium; group 4: high iodine diet and Carbimasole. Oxidative stress markers such as lipid peroxides were determined in thyroid gland, hepatic tissue and in blood. Measuring H+ donor ability of the sera and catalase activity in thyroid gland and in hepatic tissue assessed antioxidant defense. Iodide excess had prooxidant effects, leading to an increased lipid peroxides level and catalase activity in target tissues and in blood and to a decreased H+ donor ability of the sera. Selenium supplementation had opposite effects. Present data allow us to conclude that the alterations due to iodide excess in thyroid gland, hepatic tissue and in blood are mediated through oxidative stress.

Characterization of iodide retention on Callovo-Oxfordian argillites and its influence on iodide migration

Abstract: Iodine-129 is commonly considered to belong to the largest contributors to the calculated impact on health associated with the long-term nuclear underground waste disposal. Its behaviour in Callovo-Oxfordian argillites, an argillaceous host rock studied by ANDRA, therefore must be fully characterized. Investigated cores have been extracted from a place outside the Meuse/Haute Marne underground laboratory. Thus, batch and through-diffusion experiments were performed to investigate iodide sorption and transport, on two different test samples. Batch experiments give evidence of a kinetically limited slight retention of iodide at low total iodine concentration. This sorption, dependent on the oxic/anoxic conditions, has been modelled with an initial quick reaction and a long-term steady loss of iodide from the solution. Through-diffusion experiments have confirmed this retention but to a lower extent than observed in batch experiments and differences were found between both samples. These differences have been explained by anionic exclusion, which potentially blocks sorption site access.

Effects of administration of iron, iodine and simultaneous iron-plus-iodine on the thyroid hormone profile in iron-deficient adolescent Iranian girls.

Abstract: To investigate whether iron supplementation can improve thyroid hormone function in iron-deficient adolescent girls A double-blind randomized intervention study The study was performed from 2002 through 2003 in the Islamic Republic of Iran 103 iron-deficient non-anaemic girls who fulfilled all inclusion criteria were included, and 94 subjects successfully completed the study Patients were randomly assigned to one of four groups and treated with a single oral dose of 190 mg iodine plus 300 mg ferrous sulphate 5 times/week (n=24), 300 mg ferrous sulphate 5 times/week (n=23), a single oral dose of 190 mg iodine (n=25), or a placebo (n=22) for 12 weeks All groups were comparable at baseline After the intervention, there was a significant increase in ferritin and transferrin saturation in the iron+iodine group (176 vs 87 μg/dl, and 188 vs 72%, respectively, P<0001 for both) and in the iron group (P<0001 for both) Urinary iodine doubled in the iron+iodine group and in the iodine group (P<0001 for both) Thyroid indices tT4, tT3 and T3RU increased and reverse RT3 decreased in the iron+iodine group (10 vs 89 μg/dl, P< 0001; 143 vs 138 μg/dl, P<005; 323 vs 284%, P<0001 and 248 vs 442 ng/dl, P<0001, respectively) and in the iron group These two groups did not differ for any of the four indices, but both differed significantly from the iodine and placebo groups Our results indicate that improvement of iron status was accompanied by an improvement in some indices of thyroid hormones This study was supported by the Dean of Research Affairs of the Tehran University of Medical Sciences

Controlled Radical Ab Initio Emulsion Polymerization of n-Butyl Acrylate by Reverse Iodine Transfer Polymerization (RITP): Effect of the Hydrolytic Disproportionation of Iodine

Abstract: Controlled radical polymerization of n-butyl acrylate by reverse iodine transfer polymerization (RITP) was achieved in ab initio emulsion polymerization to yield a stable and uncolored latex (particle diameter d p = 106 nm). Hydrolysis of iodine, I 2 , was responsible for an upward deviation from the targeted molecular weight M n,targeted = 10400 g mol -1 . The iodide concentration [I - ] was followed by an iodide selective electrode and the amount of efficient iodine (33%) was successfully correlated with the experimental molecular weight M n,exp = 31 000 g · mol -1 . Finally, a simplified mechanism of RITP in ab initio emulsion polymerization taking into account the iodine hydrolysis was proposed.

Treatment with drugs able to reduce iodine efflux significantly increases the intracellular retention time in thyroid cancer cells stably transfected with sodium iodide symporter complementary deoxyribonucleic acid.

Abstract: Context: One of the major limits of gene therapy with sodium iodide symporter (NIS), which enables cells to be subjected to radioiodine therapy, is that NIS-transfected cells rapidly release the intracellular iodine. Methods: We transfected human anaplastic (FRO) and medullary (TT) thyroid cancer-derived cell lines that were unable to take up iodine with human NIS cDNA. The possibility of increasing the iodine retention time by treating the transfected clones with myricetin, lithium, 17-(allylamino)-17-demethoxygeldanamycin (17-AAG), and 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS) was explored. Results: We obtained 19 FRO and 16 TT clones stably transfected with NIS. Twelve of 19 FRO and nine of 16 TT clones expressed the full-length NIS mRNA; 11 of 12 FRO and four of nine TT clones were able to take up radioiodine and correctly expressed NIS protein on the plasma membrane. Kinetic analysis of iodide uptake in the two clones (FRO-19 and TT-2) with the highest uptaking activity revealed that ...

Effect of water on the functionalization of substituted anisoles with iodine in the presence of F-TEDA-BF4 or hydrogen peroxide.

Abstract: Water was found to be a convenient reaction medium for functionalization of substituted anisoles using iodine in the presence of Selectfluor F−TEDA−BF4 or hydrogen peroxide as mediators and oxidizers. Two types of functionalization were observed: iodination or oxidation. In the iodination process, two reaction routes were established. In the case of the first route, a high iodine atom economy was achieved for selective and effective iodo functionalization with a stoichiometric ratio of substrate/iodine/(mediator/oxidizer) = 2:1:1.2. An electrophilic iodination reaction process was suggested for this route, with the oxidizer converting the liberated iodide anion to iodine. For the second reaction route, a stoichiometric ratio of substrate/iodine/(mediator/oxidizer) = 1:1:1 and a lower iodine atom economy were observed; in this case, ion radical formation in the first step of the reaction was suggested. Iodine was found to be an effective catalyst for the oxidation of a hydroxy benzyl functional group to b...

Direct Iodination of Aromatic Compounds with Polyvinylpyrrolidone Supported Hydrogen Peroxide (PVP‐H2O2) and Potassium Iodide or Molecular Iodine

Abstract: Hydrogen peroxide was supported on polyvinylpyrrolidone to afford a stable and mild oxidizing reagent. Activated aromatic compounds were reacted with PVP-H2O2 in the presence of KI or I2 and a catalytic amount of H3PW12O40 in refluxing CH2Cl2 to afford the corresponding iodinated arenes.

Determination of intrathyroidal iodine by X-ray fluorescence analysis in 60- to 65-year olds living in an iodine-sufficient area

Abstract: Objectives. X-ray fluorescence (XRF) is a non-invasive method for determining the iodine content of the thyroid gland in vivo. In spite of the obvious clinical value of such a method in situations ...

The distributions of iodate and iodide in Rogoznica Lake (East Adriatic Coast)

Abstract: This study was performed in order to obtain information on the influence of an acute anoxic event (September, 1997) on distribution and speciation of inorganic iodine in the water column of a small, intensely eutrophicated salt lake. The variations in iodate and iodide depth distributions during the investigated period (1998–2000) were in accord with seasonal changes in redox conditions. During the stratification period (spring and summer), the concentration ratio between iodate and iodide in the upper layers was high, whereas during late summer and autumn, as a result of water column de-stratification and mixing of highly reducing deep water with the oxic layer, lower ratios and more uniform depth distributions were observed. The massive mortality of lake organisms induced by anoxic conditions and sulphide presence throughout the water column was registered by the end of September 1997, when overturn of the lake occurred. The concentrations of iodate in the oxic upper layers were elevated for more than a year after the mass-mortality event (up to 0.55 μmol L −1 ), whereas iodide concentrations remained high for more than 2 years in deep anoxic water (up to 2.27 μmol L −1 ). These data suggest that biogeochemical renewal processes affecting the concentrations of inorganic iodine in the lake water are slow compared to those that govern the speciation of iodine. The role of sediment–water interactions and iodine-rich organic species in the production of iodide are discussed.